In order to meet the strong desires of a person who wishes to be healthy throughout life in response to an aging society, many health classes are held as a group in places with broad floor areas such as gymnasiums or the like in respective regions. On the other hand, there has been a demand for development, commoditization and promotion of a simple health promotion instrument for managing individual health during work breaks in any narrow place such as at home or at the sides of an aisle at work. The introduction for promotional purposes of slow step exercises under such circumstances came from recent news reports such as television program “Tamesitegatten” of NHK in Aug. 5, 2009, which may be searched and downloaded from the internet, and Fukuoka City News Chuo Ward Edition (Feb. 15, 2010).
As an example, in a web store, “Rakuten Ichiba”, a step platform for slow step exercises used in slow step exercises is sold as a plastic product having the product name of “STEPWELL 2 (Combi Wellness Corporation)” or a wooden product having a product name of “Slow Step 500”. Among these, as one example in the product specification for STEPWELL 2, the body is formed of plastic (PP+ABS) so that the horizontal width is 800 millimeters, the depth is 300 millimeters, and the height is adjusted in five levels at intervals of 25 millimeters from 100 millimeters to 200 millimeters by a height adjusting block component with a weight of the body of about 3.6 kg and the weight limit thereof in use of 100 kg. In JP 2007-205146 A, a step platform is provided for use in working at high places that is aimed at not damaging objects even in the event of a collision in interior construction sites. At such a site, there is a need to provide a lightweight step platform in which an anti-slip rubber is adhered to a surface of a styrene foam solid block, but there is no concept of a step platform for slow step exercises. Further, in JP 2007-051484 A, there is provided a home step platform having a height adjusting step frame used for reinforcing leg strength.
In the step platform for slow step exercises which is mentioned above and has been sold conventionally as a product, the total weight and size are inconvenient for use by an elderly person who wish to maintain and enhance health or comparatively weak people who need to improve leg strength when handling the step platform (for example, when carrying it to an exercise place, setting the height, and the like). Further, in order to use the step platform as a simple health promotion instrument for managing individual health during work breaks in narrow spaces at home and or work places, there are the problems of decreases in the weight and size of the step platform, ease of adjustment of the height thereof, and ease of setup regardless of the place. JP 2007- 205146 A introduces a lightweight step platform in which the anti-slip rubber is adhered to the styrene foam solid block. Further, the step platform adhered with the anti-slip rubber is used to prevent loosing one's footing on the step platform, but there is no description that the rectangular parallelepiped styrene foam is used in consideration of the small load bearing strength so that the load is distributed in the step plate. Further, regarding the height of the step platform, there is no description other than an examination of use in which the height is increased by stacking the rectangular parallelepiped step platforms. As described above, it was considered that a step platform using a conventional styrene foam generally used with an expansion ratio of 60 times could be used to hold a person only with a solid structure. Further, step platforms which use a conventional styrene foam are not used as a fixture for an extremely large number of mounting and dismounting.
Next, in the related art described below, the problem of a step platform having a hollow body or a hollow space is illustrated. In JP H10-131282 A, since a substantially box-like hollow body with an upper opening portion is formed in a step platform for access to a back door many of which do not have steps in Japan with the hollow portion to be used for a water outlet, the upper opening portion including a drain tank increases in size. Therefore, it is considered that the material of this step platform would have insufficient load bearing strength with normal foam. Accordingly, in this case, glass fiber reinforced polyurethane foam is exemplified as the foam. In JP 2000-248706 A, a step platform for access to a back door is formed of synthetic resin foam and the step platform and a step portion are all formed in a hollow box shape of which a lower end is opened, and a reinforcement rib, a reinforcement wall, and the like are formed therein so as to improve the load bearing strength. Further, an underlying net is interposed between the upper coating surface of the step platform and the step portion and the foam so as to reinforce load strength. In JP H10-231672 A, a resin foam block built in a step forming portion of a step-shaped step platform for access to a door is formed of a 30 to 45 times expanded polystyrene, and is densely charged inside the step forming portion. Further, even in this case, the opening portion of the hollow body is large, and the step platform is reinforced by inner and outer annular ribs and a lattice-shaped rib, and further reinforcing metal pipe.
From the above-described disclosed documents, in a step platform having a hollow body or the hollow space and having a large opening portion, it is considered that some kind of reinforcement is essential. Accordingly, in a step platform using a normal styrene foam with an expansion ratio of 60 times, in order to satisfy the load bearing strength, there is a need to limit the relatively small opening portion to a size equal to or smaller than a predetermined opening portion corresponding to the magnitude of the load. Further, at this time, even in a case where the step platform is used as a unit in which the number of times of mounting and dismounting the step platform is extremely large, there is a need to realize durability for sufficient use.
Even in such circumstances, there is a need to develop a compact step platform for slow step exercises which is light in weight, with a load bearing performance, durability, and a height adjusting function. Furthermore, there is a need to develop a compact step platform for slow step exercises with a function for displaying the number of times or count of mounting and dismounting the step platform, which is considered to be essentially necessary for increasing the so-called incentive of encouraging a user.